128 MR. O. SALVIN ON BIRDS FROM [Feb. 4, 



I may add that in a Bat {Pieropus medius) I found the superior 

 oblique to have a relation like that in the Lemur to the superior 

 rectus, but the inferior oblique was close up to the corneal limit. 



It may be also proper to state that these variations in the muscu- 

 lar attachments do not appear to depend in any definite manner on 

 alterations in the position of the orbit. M. Broca, in the ' Revue 

 J' Anthropologic,' 1877, p- 356, gives a table of the obliquity of the 

 orbit in meinbers of the Quadrumana, this obliquity being determined 

 by measuring the angle between the base-line of the skull (in his 

 series the base-line chosen is the plane of the foramen magnum) and 

 the axis of the orbit. This axis is a line passing outwards and for- 

 wards from the optic foramen through the centre of the orbital 

 aperture. From this direction of the axis it will be seen (a) that 

 it does not correspond with the visual axis, (h) that its obliquity 

 is made up of an obliquity to the median plane of the head and of 

 an obliquity to the horizontal base-line of the skull. 



As instances of the great varieties found in this angle, he gives 

 the mean angle in Orang as 4.5°"G2, Cereopithecus 28°'43, Cebus 

 22°-3, Mycetes 67°- 17, Lemurs 41°-05. 



It seems possible that a comparison of the angles between the two 

 visual axes when the eyes are at rest, would be more likely to afford 

 some explanation of the meaning of the gradual change in the rela- 

 tive position of the eye-muscles ; and the direction of these axes it 

 appears at present to be impossible accurately to ascertain. 



5. On some Birds transmitted from the Samoan Islands by 

 the llev. T. Powell. By Osbert Salvin, M.A., F.R.S. 



[Eeceived January 6, 1879.] 



The collection, which contained specimens of the following five 

 species of birds, was placed in my hands by Mr. Sclater, because there 

 were two Petrels amongst them, a family of birds to which I have 

 lately paid considerable attention. The skins were obtained by the 

 Rev. Thomas Powell, of Faleatili, Upolu, Samoan Islands, during a 

 visit to the islands of Tutuila and Manoa, the two easternmost islands 

 of the group, and transmittted to Mr. Sclater, with a request that he 

 would have them named. This I have endeavoured to do, but have 

 only succeeded in finding names for th.ree of the five species, the 

 other two being apparently undescribed : — 



1. PiNAROLESTES POWELLI, Sp. nOV, 



Saturate brunneus, alls et cauda nigricantlo7-ibus ; abdomine 

 rufescenti-brunneo ; rectricibus tribus utrinque ejctimis albo 

 terminatis ; rostro et pedihus plumbeo-corneis. Lonij. tot. 7'0, 

 al(S 31, caudce 3'2, tarsi ()9, rostri a riclii TI. 



Hub. Tutuila, Samoan Islands (T. Powell). 



Ofis. Sp. P. vitiensi affinis, sed major, alis et cauda saturating 

 brunncis. 



